A neuropsychological theory of attention is described in which the encoding of one stimulus interferes with the encoding of other stimuli. This interference effect is termed cognitive masking and is attributed to recurrent lateral inhibition between neurons in association cortex. Evidence is reviewed which indicates that there is a facilitation of cortical recurrent inhibition during arousal, and it is suggested that cognitive masking is related to the level of arousal. A mathematical model is presented which describes the activity of sets of cortical neurons having reciprocal inhibitory interconnections. The results of some computer simulations of this model indicate that the model can account for cognitive masking and several other attentional effects. Implications of the theory for a variety of problems are discussed.

In a spatial version of the Stroop task where subjects must attend to the position of a word and ignore the word itself, we argue that interference results because selective attention is only partially successful. If so, then increasing attention to the word should increase interference. Experiment 1 showed increased interference with position naming when subjects must be prepared to attend to either the word or its position. Experiment 2 required subjects to first name the position of the word and then later to recall which word had been presented. This resulted in increased interference with position naming when the word was followed at a short SOA by a pattern mask. Experiment 3 employed both word reading and position naming and showed that a large reverse Stroop effect occurred with both vocal and manual responses when subjects had to be prepared to attend to either dimension of the stimulus.

Naive cats cannot use thalamic stimulation as a signal to perform a behavioral response when stimulus intensities are too weak to evoke orienting behavior. Responses are quickly learned at higher intensities of stimulation, and with continued training, the cats become able to response to the weaker, previously ineffective stimulus. This increase in sensitivity is not due to changes in tonic arousal and appears to be relatively specific to the stimulated nucleus. The procedures may be useful in exploring the neural mechanisms of perceptual learning.

It is argued that the position recently attacked by Feeney, Pittman, and Wagner is a "straw man" based on misinterpretations of the theory presented in 1973 by Walley and Weiden. We attempt to show that the Walley and Weiden theory can account for the data discussed by Feeney, Pittman, and Wagner, as well as additional data not cited by these authors.

The present study examined characteristics of comparable samples of patients admitted to nonaffiliated day and full-time psychiatric hospitals. Moreover, the influence of the day hospital program on symptomatology and social functioning was assessed. In general, the results indicated that day patients were of higher socioeconomic status and had fewer previous hospitalizations in comparison to 24-hour patients. While fewer day patients were diagnosed as psychotic, they did obtain higher scores of social inadequacy, depression and social introversion. Participation in the day hospital program was generally found to be related to decreased psychopathology, increased self-esteem and social role activities, and symptom relief. However, patients suffering from functional psychoses were found to demonstrate improvement below the average of the patient sample. These results were discussed in relation to previous research.